Marvell International Limited

Lsi Corporation

Avago Technologies General IP (singapore) Pte. Ltd.

Parviz Rahgozar

Haitao Xia

Ming Jin

Wu Chang

Pantas Sutardja

Kien Beng Tan

Variations of the Nelder-Mead direct search method are employed to find read channel parameter settings in a discrete field having three or more dimensions. The three or more dimensions correspond to read channel parameters, at least some of which are highly correlated. The steps of the Nelder-Mead method are executed according to a methodology to arrive at substantially optimal parameter settings for a read channel, even where a discrete function defining parameter outcomes is noisy. In some embodiments, dimensional collapse, considered inefficient in a two-dimensional field, is allowed in order to reach an optimal solution in a greater-than-two-dimensional field.

Multi-dimensional optimization of read channel

In one embodiment, a read/write chip for a hard disc drive has at least one on-chip, in-channel, hardware-based optimization processor that is part of one or more channels (e.g., read, write, and/or servo) of the read/write chip. The optimization processor can iteratively evaluate the performance of a channel for different values of one or more different parameters that control channel processing by generating an appropriate metric value for each different parameter value. The optimization processor can then select an optimal parameter value for subsequent channel processing.

In-channel channel optimization for hard-disc drive read/write chips

In one embodiment, the present invention includes an apparatus that includes a circuit that generates control information that controls a height of a read head of a disk drive. The circuit comprises a filter circuit and a detector circuit. The filter circuit receives a read channel signal from the read head and generates a filtered signal. The filtered signal ranges between 1.0 kHz and 500 kHz. The detector circuit receives the filtered signal and generates the control information when the filtered signal exceeds a defined threshold.

Fly-height touchdown detection circuits and methods

A system includes N channels and a control module. Each of the N channels includes a latch and a signal generator module, where N is an integer greater than 1. The latch selectively latches a B-bit codeword, where B is an integer greater than 1. The signal generator module generates a signal based on the B bit codeword. The control module transmits the B-bit codeword via a B-bit data bus to the latch of each of the N channels. The control module generates control signals that select the latch in at least one of the N channels.

Self servo write tune feature for preamps

Circuits, architectures, a system and methods for adjusting spacing between a data writing mechanism and a data storage medium. The circuit generally includes (a) adjustment logic configured to (i) determine a first length of time of a write operation to a data storage medium, and (ii) determine a second length of time between the first write operation and a second write operation, (b) a controller configured to adjust a state variable of a write signal to a mechanism that writes data to the storage medium in accordance with the first and second lengths of time, and (c) an output circuit providing the write signal to the write mechanism. The method generally includes the steps of (1) determining a first length of time for a first write operation; and (2) determining a second length of time between the first write operation and a second write operation; and (3) adjusting at least one state variable of a write signal provided to the data writing mechanism in accordance with the determining steps. The present invention advantageously reduces adverse spacing modulation between the writing mechanism and the storage medium, thereby enabling improved data integrity, reduced bit error rates, and 'cold write' operations.

Circuits, architectures, apparatus, systems, and methods for maintaining constant spacing in a read/write apparatus for data storage

Circuitry, systems, and methods for measuring the fly height of a read/write head in a magnetic data storage system. The circuitry generally includes a capacitance measurement circuit configured to measure the capacitance between the read/write head and the surface of the magnetic recording medium (or a derivative of that capacitance), and a fly height converter configured to produce an output signal corresponding to the fly height based on the measurement. The capacitance measurement circuit is generally configured to receive a periodic signal with a generally constant voltage slew rate coupled to the read/write head. The present invention advantageously provides for electronically measuring the fly height of a read/write head in situ in a magnetic storage system. The sensed fly height may then be used by the system to control fly height actuation.

Circuits, systems, and methods for capacitive fly height measurement

Circuitry, systems, and methods for measuring the fly height of a read/write head in a magnetic data storage system. The circuitry generally includes a capacitance measurement circuit configured to measure the capacitance between the read/write head and the surface of the magnetic recording medium (or a derivative of that capacitance), and a fly height converter configured to produce an output signal corresponding to the fly height. The capacitance measurement circuit generally includes an input receiving a periodic signal with a generally constant voltage slew rate, coupled to the read/write head, and a current measuring circuit coupled to the read/write head. The present invention advantageously provides for electronically measuring the fly height of a read/write head in situ in a magnetic storage system. The sensed fly height may then be used by the system to control fly height actuation.

Growing community of inventors

Cupertino, CA, United States of America

Parviz Rahgozar